Characterization of a novel SCN5A mutation associated with long QT syndrome and arrhythmogenic right ventricular cardiomyopathy in a family.

Sudden cardiac death represents a significant diagnostic challenge for forensic pathologists, particularly in inherited arrhythmia syndromes or cardiomyopathies resulting from genetic defects. Molecular autopsies can reveal the underlying molecular etiology in such cases. In this study, we investigated a family with a history of sudden cardiac death to elucidate the molecular basis responsible for sudden cardiac death. The proband underwent a comprehensive forensic examination. Family members received thorough clinical evaluations, including electrocardiogram, Holter monitoring, echocardiography, and cardiac magnetic imaging. Whole exome sequencing and genetic analysis were performed on the deceased and her parents. In addition, Western blotting and patch-clamp recordings were employed to evaluate the expression and function of the mutant protein in vitro. Forensic examination diagnosed arrhythmogenic right ventricular cardiomyopathy (ARVC) as the cause of sudden death. Genetic analysis identified a novel missense mutation in SCN5A (p.V1323L), which was assessed as likely pathogenic by the ACMG guideline. Another family member carrying the mutation manifested long QT syndrome and mild cardiac fibrosis. The cellular electrophysiological study demonstrated that the mutation resulted in an enhanced late sodium current, suggesting it was a gain-of-function mutation. This study characterizes a novel SCN5A mutation that putatively causes long QT syndrome and may contribute to the development of ARVC. Our work expands the pathogenic spectrum of SCN5A variants and underscores the importance of molecular autopsy in sudden death cases, especially in those with suspected genetic disorders.

Targeted genetic analysis in a cohort of sporadic death from spontaneous rupture of thoracic aortic dissection in Han Chinese population.

PURPOSE: Thoracic aortic dissection (TAD) is a life-threatening cardiovascular disease that often results in sudden cardiac death (SCD). However, the genetic characteristics of individuals with TAD confirmed at autopsy have been rarely studied. Our objective was to determine the prevalence of pathogenic variants in TAD-associated genes in a cohort of sporadic deaths resulting from spontaneous rupture of TAD and identify relevant genotype-phenotype relationships in Han Chinese population. METHODS: We included sixty-one consecutive sporadic decedents whose primary cause of death was spontaneous rupture of TAD, and performed a whole exome sequencing based strategy comprising 26 known TAD-associated genes. RESULTS: We identified 7 pathogenic or likely pathogenic (P/LP) variants in 7 cases (11.48 %) and 22 variants of uncertain significance (VUS) in 22 cases (36.07 %). The FBN1 gene was found to be the major disease-causing gene. Notably, TAD decedents with P/LP variant exhibited significantly earlier mortality. Moreover, we reported for the first time that TAD decedents with P/LP variant had a shorter diagnosis and treatment time. CONCLUSION: Our study investigated the genetic characteristics of TAD individuals confirmed until autopsy in Han Chinese population. The findings enhanced the understanding of the genetic underpinnings of TAD and have significant implications for clinical management and forensic investigations.

Transcription factor Hoxb5 reveals the unidirectional hierarchy of hematopoietic stem cell pool.

Hoxb5 exhibits preferential expression in hematopoietic stem cells (HSCs) and uniquely marks the long-term HSCs (LT-HSCs). Previous studies have demonstrated the remarkable capability of Hoxb5 to alter cell fates when enforced expression in blood progenitors, such as B cell progenitors and multipotent progenitors. Additionally, Hoxb5 deficiency does not hinder the generation of LT-HSCs. However, the specific impact of Hoxb5 deletion on LT-HSCs has remained unexplored. To address this, we developed a conditional Hoxb5 knockout-reporter mouse model, wherein Hoxb5 was knock out by the Vav-cre recombinase, and the endogenous Hoxb5 promoter drove the expression of the blue fluorescent protein (BFP). Our findings revealed that the primary recipients, who transplanted with HSCs indicating Hoxb5 deficiency by the presence of BFP (BFP-positive HSCs), exhibited comparable levels of donor chimerism and lineage chimerism to recipients transplanted with HSCs that spontaneously did not express Hoxb5 and thus lacked BFP expression (BFP-negative HSCs). However, during the secondary transplantation, recipients receiving total bone marrow (BM) from the primary recipients with BFP-positive HSCs showed significantly higher levels of donor chimerism and more robust multi-lineage chimerism compared to those receiving total BM from the primary recipients with BFP-negative HSCs. Our results indicate that deleting Hoxb5 in LT-HSCs transiently influences their lineage differentiation bias without compromising their long-term self-renewal capacity. These findings highlight the primary role of Hoxb5 in regulating lineage commitment decisions in LT-HSCs, while emphasizing that its presence is not indispensable for the maintenance of long-term self-renewal capacity.

RAF1 mutation leading to hypertrophic cardiomyopathy in a Chinese family with a history of sudden cardiac death: A diagnostic insight into Noonan syndrome.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is predominantly caused by mutations in sarcomeric genes. However, a subset of cases is attributed to genetic disorders unrelated to sarcomeric genes, such as Noonan syndrome (NS) and other RASopathies. In this study, we present a family with a history of sudden cardiac death (SCD) and focus on two adults with syndromic left ventricular hypertrophy (LVH). METHODS: Clinical evaluations, including echocardiography, were conducted to assess cardiac manifestations. Whole-exome sequencing was performed to identify potential genetic variants underlying syndromic LVH in the study participants. RESULTS: Whole-exome sequencing revealed a missense variant in the RAF1 gene, c.782C>T (p.Pro261Leu). This variant confirmed the diagnosis of NS in the affected individuals. CONCLUSION: The findings of this study underscore the importance of family history investigation and genetic testing in diagnosing syndromic LVH. By identifying the underlying genetic cause, clinicians can better understand the etiology of RAS-HCM and its association with SCD in young adults.

Mutation in mitral valve prolapse susceptible gene DCHS1 causes familial mitral annular disjunction.

BACKGROUND: Mitral annular disjunction (MAD) is an under-recognised phenotype associated with severe ventricular arrhythmias. Limited knowledge has been gained on its molecular genesis. METHODS: A total of 150 unrelated deceased Chinese were collected for whole-exome sequencing, with analysis focusing on a panel of 118 genes associated with 'abnormal mitral valve morphology'. Cases were prespecified as 'longitudinally extensive MAD (LE-MAD)' or 'longitudinally less-extensive MAD (LLE-MAD)' according to the gross disjunctional length with a cut-off of 4.0 mm. The pedigree investigation was conducted on a case carrying an ultra-rare (minor allele frequency <0.1%) deleterious variant in DCHS1. RESULTS: Seventy-seven ultra-rare deleterious variants were finally identified. Exclusively, 12 ultra-rare deleterious variants distributed in nine genes occurred in LE-MAD, which were ANK1, COL3A1, DCHS1, FBN2, GNPTAB, LZTR1, PLD1, RYR1 and VPS13B. Ultra-rare deleterious variants in those nine genes were predominantly distributed in LE-MAD compared with LLE-MAD (28% vs 5%, OR 7.30, 95% CI 2.33 to 23.38; p<0.001), and the only gene related to LE-MAD with borderline significance was DCHS1. LE-MAD was consistently observed in a sizeable Chinese family, in which LE-MAD independently co-segregated with an ultra-rare deleterious variant in DCHS1, rs145429962. CONCLUSION: This study initially proposed that isolated LE-MAD might be a particular phenotype of MAD with a complex genetic predisposition. Deleterious variants in DCHS1 might be associated with the morphogenesis of LE-MAD.

Retinol dehydrogenase 10 reduction mediated retinol metabolism disorder promotes diabetic cardiomyopathy in male mice.

Diabetic cardiomyopathy is a primary myocardial injury induced by diabetes with complex pathogenesis. In this study, we identify disordered cardiac retinol metabolism in type 2 diabetic male mice and patients characterized by retinol overload, all-trans retinoic acid deficiency. By supplementing type 2 diabetic male mice with retinol or all-trans retinoic acid, we demonstrate that both cardiac retinol overload and all-trans retinoic acid deficiency promote diabetic cardiomyopathy. Mechanistically, by constructing cardiomyocyte-specific conditional retinol dehydrogenase 10-knockout male mice and overexpressing retinol dehydrogenase 10 in male type 2 diabetic mice via adeno-associated virus, we verify that the reduction in cardiac retinol dehydrogenase 10 is the initiating factor for cardiac retinol metabolism disorder and results in diabetic cardiomyopathy through lipotoxicity and ferroptosis. Therefore, we suggest that the reduction of cardiac retinol dehydrogenase 10 and its mediated disorder of cardiac retinol metabolism is a new mechanism underlying diabetic cardiomyopathy.

Hepatocyte Ninjurin2 promotes hepatic stellate cell activation and liver fibrosis through the IGF1R/EGR1/PDGF-BB signaling pathway.

BACKGROUND: Liver fibrogenesis is orchestrated by the paracrine signaling interaction between several resident cell types regulating the activation of hepatic stellate cells (HSCs). However, the molecular mechanisms underlying paracrine regulation are largely unknown. The aim of this study is to elucidate the role of Ninjurin2 in the crosstalk between hepatocytes and HSCs and better understand the implications of Ninjurin2 in liver fibrosis. METHODS: Ninj2 knockout mice (Ninj2-/-) and hepatocyte-specific Ninj2 overexpression mice (Ninj2Hep-tg) were constructed and followed by the induction of liver fibrosis using methionine- and choline-deficient (MCD) diet. The relationship between Ninjurin2 and liver fibrosis phenotype was evaluated in vivo by measurement of fibrotic markers and related genes. We used an in vitro transwell cell co-culture model to examine the impact of Ninjurin2 in hepatocytes on the crosstalk to HSCs. The interaction of Ninjurin2 and IGF1R and the regulation of PI3K-AKT-EGR1 were analyzed in vivo and in vitro. Finally, an inhibitory Ninjurin2 peptide was injected intravenously via the tail vein to investigate whether inhibiting of Ninjurin2 cascade can attenuate MCD diet-induced liver fibrosis in mice. RESULTS: We found that hepatic Ninjurin2 expression was significantly increased in fibrotic human liver and MCD diet-induced liver injury mouse models. In the mouse model, hepatocyte-specific overexpression of Ninj2 exacerbates MCD-induced liver fibrosis, while global Ninj2 knockout reverses the phenotype. To mimic hepatocyte-HSC crosstalk during liver fibrosis, we used co-culture systems containing hepatocytes and HSCs and determined that Ninjurin2 overexpression in hepatocytes directly activates HSCs in vitro. Mechanistically, Ninjurin2 directly interacts with insulin-like growth factor 1 receptor (IGF1R) and increases the hepatocyte secretion of the fibrogenic cytokine, platelet-derived growth factor-BB (PDGF-BB) through IGF1R-PI3K-AKT-EGR1 cascade. Inhibition of PDGFRB signaling in HSCs can abolish the profibrogenic effect of Ninjurin2. In addition, we demonstrated that a specific inhibitory Ninjurin2 peptide containing an N-terminal adhesion motif mitigates liver fibrosis and improves hepatic function in the mouse models by negatively regulating the sensitivity of IGF1R to IGF1 in hepatocytes. CONCLUSION: Hepatic Ninjurin2 plays a key role in liver fibrosis through paracrine regulation of PDGF-BB/PDGFRB signaling in HSCs, and the results suggesting Ninjurin2 may be a potential therapeutic target.

The characteristics of thoracic aortic dissection in autopsy-diagnosed individuals: An autopsy study.

Thoracic aortic dissection (TAD) is the most common cause of sudden cardiac death associated with aortic diseases. The age of TAD victims in forensic studies is significantly younger than hospitalized patients with TAD, while only a few studies have been conducted on autopsy-diagnosed TAD deceased. A retrospective study was conducted at the Medicolegal Center of Sun Yat-sen University from 1999 to 2019 to address the characteristics of TAD victims. A total of 200 deceased from spontaneous rupture of TAD were assessed, with 165 (82.5%) males and 175 (87.5%) Stanford type A deceased. Our main results showed that compared with patients with TAD diagnosed during their lifetime, individuals diagnosed with TAD until an autopsy showed an earlier onset (43.80 years old) and less accompanied hypertension (<50%). Sudden death was the initial symptom of 32 decedents. Instead of chest/back pain (40 decedents), abdominal pain (59 decedents) was the most common initial symptom, and 42 decedents presented with no accompanying pain. A higher proportion of abdominal pain and the painless symptom was associated with a higher risk of misdiagnosis. Women showed a more atypical clinical presentation and rapid progression than men. Younger decedents showed more pronounced left heart changes. The present study implicated the TAD individuals diagnosed until an autopsy as a particular entity, indicating the urgent need for further investigation on early diagnosis and pathogenesis of patients with TAD with atypical pain and painless or with younger age to reduce the burden of TAD-related sudden death.

Epidemiology of Sports-Related Sudden Death in Guangdong Province.

OBJECTIVES: By retrospective study of the epidemiological characteristics of sports-related sudden death (SrSD), the risk factors associated with SrSD were analyzed and explored to provide a scientific basis for comprehensive prevention and treatment of SrSD. METHODS: The personal information (sex, age, occupation, etc.), case information (time, place, type of sports, relative time between SrSD occurrence and exercise, etc.), death related information (sign or prodrome, medical history and surgical history, etc.), rescue situation (witnesses, on-site assistance, the availability of paramedics, etc.) of 374 SrSD cases in Guangdong Province from 2017 to 2021 were collected. Statistical analysis was conducted aiming at the key factors. RESULTS: In the 374 cases, there were significantly more males than females (19.78:1); the number of people aged between >39 and 59 was the largest (151, 40.37%); non-manual workers (68.98%) were more than manual workers; the top three sports with the highest number cases were basketball (34.49%), running (19.52%) and badminton (12.03%); from 3 pm to 9 pm (63.10%) was the time period with the highest incidence of events; sudden death mainly occurred during exercise (75.27%) and within 1 h after exercise (20.05%); the on-site rescue rate was very low (6.15%); the rate of autopsies was extremely low (1.07%); sudden cardiac death was the most common cause (67.11%). CONCLUSIONS: SrSD is most common in males aged >39 to 59 years old, mostly in non-manual workers, and usually occurs in basketball and running. Sudden death is more likely to occur during exercise and within 1 h after exercise. Therefore, the above potential risk factors should be focused on and studied in daily comprehensive prevention and treatment to provide scientific basis for accurate prevention and first aid of such sudden death.

Evaluation of Inspection Efficiency of Diatom Artificial Intelligence Search System Based on Scanning Electron Microscope.

OBJECTIVES: To explore the application values of diatom artificial intelligence (AI) search system in the diagnosis of drowning. METHODS: The liver and kidney tissues of 12 drowned corpses were taken and were performed with the diatom test, the view images were obtained by scanning electron microscopy (SEM). Diatom detection and forensic expert manual identification were carried out under the thresholds of 0.5, 0.7 and 0.9 of the diatom AI search system, respectively. Diatom recall rate, precision rate and image exclusion rate were used to detect and compare the efficiency of diatom AI search system. RESULTS: There was no statistical difference between the number of diatoms detected in the target marked by the diatom AI search system and the number of diatoms identified manually (P>0.05); the recall rates of the diatom AI search system were statistically different under different thresholds (P<0.05); the precision rates of the diatom AI system were statistically different under different thresholds(P<0.05), and the highest precision rate was 53.15%; the image exclusion rates of the diatom AI search system were statistically different under different thresholds (P<0.05), and the highest image exclusion rate was 99.72%. For the same sample, the time taken by the diatom AI search system to identify diatoms was only 1/7 of that of manual identification. CONCLUSIONS: Diatom AI search system has a good application prospect in drowning cases. Its automatic diatom search ability is equal to that of experienced forensic experts, and it can greatly reduce the workload of manual observation of images.

Assisting Role of Pulmonary Hypostasis Phenomenon in Diagnosis of Drowning.

OBJECTIVES: To study the phenomenon of pulmonary hypostasis in corpses of various causes of death, and to explore the potential value of this phenomenon in assisting forensic pathological diagnosis of drowning. METHODS: A total of 235 cases with clear cause of death through systematic autopsy were collected from January 2011 to June 2021 in Guangzhou. According to the location of body discovery, the cases were divided into the water body group (97 cases) and the non-water body group (138 cases), and the water body group was further divided into the water drowning group (90 cases) and the water non-drowning group (7 cases). Non-water body group was further divided into the non-water drowning group (1 case) and the non-water non-drowning group (137 cases). Three senior forensic pathologists independently reviewed autopsy photos to determine whether there was hypostasis in the lungs. The detection rate of pulmonary hypostasis was calculated. RESULTS: The detection rate of pulmonary hypostasis in the water drowning group (90 cases) was 0, and the negative rate was 100%. The detection rate of pulmonary hypostasis in the water non-drowning group (7 cases) was 100% and the negative rate was 0. The detection rate of pulmonary hypostasis in the water body group and in the non-water body group (after excluding 2 cases, 136 cases were calculated) was 7.22% and 87.50%, respectively. There were statistically significant differences in the detection rate of pulmonary hypostasis between water body group and non-water body group, and between water drowning group and water non-drowning group (P<0.05). CONCLUSIONS: The disappearance of pulmonary hypostasis can be used as a specific cadaveric sign to assist in the forensic pathological diagnosis of drowning.

Mechanosensitive Piezo1 channels mediate renal fibrosis.

Kidney fibrosis is the final common pathway of progressive kidney diseases, the underlying mechanisms of which are not fully understood. The purpose of the current study is to investigate a role of Piezo1, a mechanosensitive nonselective cation channel, in kidney fibrosis. In human fibrotic kidneys, Piezo1 protein expression was markedly upregulated. The abundance of Piezo1 protein in kidneys of mice with unilateral ureter obstruction (UUO) or with folic acid treatment was significantly increased. Inhibition of Piezo1 with nonspecific inhibitor GsMTx4 markedly ameliorated UUO- or folic acid-induced kidney fibrosis. Mechanical stretch, compression, or stiffness induced Piezo1 activation and profibrotic responses in human HK2 cells and primary cultured mouse proximal tubular cells (mPTCs), which were greatly prevented by inhibition or silence of Piezo1. TGF-ß1 induced increased Piezo1 expression and profibrotic phenotypic alterations in HK2 cells and mPTCs, which were again markedly prevented by inhibition of Piezo1. Activation of Piezo1 by Yoda1, a Piezo1 agonist, caused calcium influx and profibrotic responses in HK2 cells and induced calcium-dependent protease calpain2 activation, followed by adhesion complex protein talin1 cleavage and upregulation of integrin ß1. Also, Yoda1 promoted the link between ECM and integrin ß1. In conclusion, Piezo1 is involved in the progression of kidney fibrosis and profibrotic alterations in renal proximal tubular cells, likely through activating calcium/calpain2/integrin ß1 pathway.

Research Progress on Sport-Related Sudden Cardiac Death.

Physical exercise can reduce the overall risk of cardiovascular disease, prolong lifespan and improve the quality of life, but some studies have shown that there is a certain correlation between vigorous physical exercise and sudden cardiac death. A number of retrospective or prospective studies on sports-related sudden cardiac death (SrSCD) have been conducted at home and abroad. This article reviews the related studies on the definition, epidemiological characteristics, common causes of SrSCD and effects of excercise on cardiovascular function, pre-exercise screening and evaluation of SrSCD, in order to understand the latest research progress on SrSCD and provide clues and references for SrSCD research.

Does Anatomic Phenotype of Mitral Annular Disjunction Impact Survival? An Autopsy-Based Retrospective Study.

Controversies have been raised regarding the prevalence and potential clinical significance of mitral annular disjunction (MAD). We aim to address the anatomic characteristics of MAD and their association, if any, on survival. We retrospectively reviewed 1373 consecutive dissected hearts (1017 men, mean age at death 44.9 ± 0.4 y) and frequently detected MAD (median disjunctional length: 2.0 mm, range: 1.5 mm~8.5 mm), with the prevalence of 92.1% over the entire mitral annulus and 74.9% within the posterior annulus (pMAD). The presence of pMAD was associated with increased all-cause mortality (45 y vs. 49 y, hazard ratio [HR]: 1.28, 95% confidence interval [CI]: 1.11~1.47, p < 0.001), which persisted in the context of cardiovascular diseases (CVDs; 46 y vs. 51 y, HR: 1.33, 95% CI: 1.14~1.56, p < 0.001) but was insignificant in those without CVDs. Compared to those without pMAD, individuals with pMAD affecting the entire posterior annulus or having a mean standardized length of ≥1.78 showed other clinically significant cardiovascular phenotypes, including the enlargement of aortic annular circumferences and a higher occurrence of thoracic aortic aneurysm/dissection. This largest series of autopsies show that MAD is a common phenotype that may exert additive influence on the survival of individuals. It is necessary to establish a precise classification and stratification of MAD.

Loss of Endothelial Hypoxia Inducible Factor-Prolyl Hydroxylase 2 Induces Cardiac Hypertrophy and Fibrosis.

Background Cardiac hypertrophy and fibrosis are common adaptive responses to injury and stress, eventually leading to heart failure. Hypoxia signaling is important to the (patho)physiological process of cardiac remodeling. However, the role of endothelial PHD2 (prolyl-4 hydroxylase 2)/hypoxia inducible factor (HIF) signaling in the pathogenesis of cardiac hypertrophy and heart failure remains elusive. Methods and Results Mice with Egln1Tie2Cre (Tie2-Cre-mediated deletion of Egln1 [encoding PHD2]) exhibited left ventricular hypertrophy evident by increased thickness of anterior and posterior wall and left ventricular mass, as well as cardiac fibrosis. Tamoxifen-induced endothelial Egln1 deletion in adult mice also induced left ventricular hypertrophy and fibrosis. Additionally, we observed a marked decrease of PHD2 expression in heart tissues and cardiovascular endothelial cells from patients with cardiomyopathy. Moreover, genetic ablation of Hif2a but not Hif1a in Egln1Tie2Cre mice normalized cardiac size and function. RNA sequencing analysis also demonstrated HIF-2α as a critical mediator of signaling related to cardiac hypertrophy and fibrosis. Pharmacological inhibition of HIF-2α attenuated cardiac hypertrophy and fibrosis in Egln1Tie2Cre mice. Conclusions The present study defines for the first time an unexpected role of endothelial PHD2 deficiency in inducing cardiac hypertrophy and fibrosis in an HIF-2α-dependent manner. PHD2 was markedly decreased in cardiovascular endothelial cells in patients with cardiomyopathy. Thus, targeting PHD2/HIF-2α signaling may represent a novel therapeutic approach for the treatment of pathological cardiac hypertrophy and failure.

Review and Thinking on Forensic Pathological Changes of Coronavirus-Infected Diseases.

Since the beginning of this century, three types of coronavirus have widely transmitted and caused severe diseases and deaths, which strongly indicates that severe infectious diseases caused by coronavirus infection are not accidental events. Coronavirus-infected diseases are mainly manifested by respiratory symptoms, with multiple organ dysfunctions. Precisely investigating the pathological process, characteristics and pathogenesis of coronavirus-infected diseases will be beneficial for us to understand clinical manifestations and provide targeted suggestions on prophylaxis and treatment. This paper briefly reviews the pathological findings of three known coronavirus-infected diseases, and attempts to construct the pathological spectrum of coronavirus-infected diseases, aiming to provide reference and thinking for autopsy, histopathological examination and animal infection model study of coronavirus-infected diseases.

Guide to forensic pathology practice for death cases related to coronavirus disease 2019 (COVID-19) (Trial draft).

Autopsy is of great significance for elucidating the pathological changes, pathogenesis and cause of death of Coronavirus Disease 2019 (COVID-19) and can provide a theoretical basis for scientific and accurate prevention and control of its outbreak. Based on related laws and regulations, such as the Law of the People's Republic of China on Prevention and Control of Infectious Diseases, clinical manifestations and epidemiological characteristics of COVID-19 and guidelines on the prevention and control of this epidemic, combined with the practical work of forensic pathology examinations, we developed the Guide to Forensic Pathology Practice for Death Cases Related to Coronavirus Disease 2019 (COVID-19) (Trial Draft). This guide describes the background investigation of the death cases, autopsy room requirements, personal prevention and protections, external examinations, autopsy practices and auxiliary examinations, and thus offers a reference for forensic and pathological examination institutions and staff.

The forensic pathological analysis of sport-related sudden cardiac death in Southern China.

Studies regarding sport-related sudden cardiac death (SCD) mainly focus on competitive athletes; similar data are rare in the general population, especially in China. We conducted a retrospective study (from September 1998 to August 2013) to investigate the aetiological distribution and epidemiological features of sport-related SCD in Southern China. Selections of cases are based on details, and two subgroups were established: one was the sport-related SCD group, and the other was the disease-free accident victims group which was matched with the sport-related SCD group in gender, age and year of death. Among the 3770 sudden-death cases, 1656 cases were SCD cases. A total of 65 cases (57 males) out of 1 656 SCD cases were sport-related. The age range of the 65 sport-related SCD cases was from 12 to 68 years old with a mean (35.92 ± 14.23) years old. Only two of these cases were competitive athletes. The most common circumstances of the 65 sport-related SCD cases were heavy physical labour (46.15%) and running (30.77%). The three leading forensic diagnoses were the coronary atherosclerotic disease (CAD, 28 cases), cardiomyopathy (CM, 14 cases) and sudden unexplained death (7 cases). CM was the most common forensic diagnosis in those ≤35 years old, while CAD was the most common one in those >35 years old. Left anterior descending in which atherosclerotic plaques was most commonly found was the principal artery branch associated with sport-related SCD. There was a statistically significant difference in the weight of hearts between the 65 sport-related SCD cases and 65 diseases-free accidental cases. This study highlights the need to attract public attention to sport-related SCD and to issue a prevention strategy to the public, and to make the SCD-related genetic sequencing a routine tool in both forensic pathological examination and clinic screening.

Distinct cardiac energy metabolism and oxidative stress adaptations between obese and non-obese type 2 diabetes mellitus.

Background: Little is known about the pathophysiological diversity of myocardial injury in type 2 diabetes mellitus (T2DM), but analyzing these differences is important for the accurate diagnosis and precise treatment of diabetic cardiomyopathy. This study aimed to elucidate the key cardiac pathophysiological differences in myocardial injury between obese and non-obese T2DM from mice to humans. Methods: Obese and non-obese T2DM mouse models were successfully constructed and observed until systolic dysfunction occurred. Changes in cardiac structure, function, energy metabolism and oxidative stress were assessed by biochemical and pathological tests, echocardiography, free fatty acids (FFAs) uptake fluorescence imaging, transmission electron microscopy, etc. Key molecule changes were screened and verified by RNA sequencing, quantitative real-time polymerase chain reaction and western blotting. Further, 28 human heart samples of healthy population and T2DM patients were collected to observe the cardiac remodeling, energy metabolism and oxidative stress adaptations as measured by pathological and immunohistochemistry tests. Results: Obese T2DM mice exhibited more severe cardiac structure remodeling and earlier systolic dysfunction than non-obese mice. Moreover, obese T2DM mice exhibited severe and persistent myocardial lipotoxicity, mainly manifested by increased FFAs uptake, accumulation of lipid droplets and glycogen, accompanied by continuous activation of the peroxisome proliferator activated receptor alpha (PPARα) pathway and phosphorylated glycogen synthase kinase 3 beta (p-GSK-3ß), and sustained inhibition of glucose transport protein 4 (GLUT4) and adipose triglyceride lipase (ATGL), whereas non-obese mice showed no myocardial lipotoxicity characteristics at systolic dysfunction stage, accompanied by the restored PPARα pathway and GLUT4, sustained inhibition of p-GSK-3ß and activation of ATGL. Additionally, both obese and non-obese T2DM mice showed significant accumulation of reactive oxygen species (ROS) when systolic dysfunction occurred, but the NF-E2-related factor 2 (Nrf2) pathway was significantly activated in obese mice, while was significantly inhibited in non-obese mice. Furthermore, the key differences found in animals were reliably verified in human samples. Conclusion: Myocardial injury in obese and non-obese T2DM may represent two different types of complications. Obese T2DM individuals, compared to non-obese individuals, are more prone to develop cardiac systolic dysfunction due to severe and persistent myocardial lipotoxicity. Additionally, anti-oxidative dysfunction may be a key factor leading to myocardial injury in non-obese T2DM.